POV-Ray : Newsgroups : moray.win : subdivision of mesh causes distortion of UV map Server Time
28 Mar 2024 11:19:22 EDT (-0400)
  subdivision of mesh causes distortion of UV map (Message 1 to 7 of 7)  
From: Steve Shelby
Subject: subdivision of mesh causes distortion of UV map
Date: 31 Oct 2004 09:31:57
Message: <4184f75d@news.povray.org>
I made a mesh maple leaf and used a bump map for the veins. It looks fine as 
long as I don't subdivide the mesh, but using a subdivision level of 1 
produces extreme distortion of the bump map. The veins zig-zag all over the 
place. It was also the same when I tried an image map. I have to use 
subdivision to make the leaf look realistic, and I have to use UV mapping, 
because I want to be able to bend the leaf and have the texture follow the 
bend. I wonder, am I going to have to re-make my mesh so that the edges 
follow the viens?
Steve Shelby


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From: Lutz Kretzschmar
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 6 Nov 2004 15:17:08
Message: <h5cqo053hf9g731h04kp9ko33cvhsocm9l@4ax.com>
Hi Steve Shelby, you recently wrote in moray.win:

> I made a mesh maple leaf and used a bump map for the veins. It looks fine as 
> long as I don't subdivide the mesh, but using a subdivision level of 1 
> produces extreme distortion of the bump map. 
Yes, there are some issues with the way that UV mapping is propagated
to the subdivided surface.
My best solution is to create the mesh with no UV mapping, set the
subdivision setting to what you want it to be, then press the Convert
to Mesh button to convert the subdivided mesh to a real mesh. Then
work with this new real mesh (which is the subdivided version of the
original mesh) and UV map that. You can keep the original around as a
hidden, non-exportable object, or you can toss it....

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray


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From: Steve Shelby
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 6 Nov 2004 18:14:04
Message: <418d5abc$1@news.povray.org>
"Lutz Kretzschmar" <lut### [at] stmuccom> wrote in message 
news:h5cqo053hf9g731h04kp9ko33cvhsocm9l@4ax.com...
> Yes, there are some issues with the way that UV mapping is propagated
> to the subdivided surface.
> My best solution is to create the mesh with no UV mapping, set the
> subdivision setting to what you want it to be, then press the Convert
> to Mesh button to convert the subdivided mesh to a real mesh. Then
> work with this new real mesh (which is the subdivided version of the
> original mesh) and UV map that. You can keep the original around as a
> hidden, non-exportable object, or you can toss it....

Thanks, Lutz. That's a little trick I was not aware of.
Since I posted the original message, I have kept working on the project, and 
have ended up making a mesh which has 3d veins as part of the mesh. I still 
had trouble when I tried to UV map the veins with a different texture. The 
color would spread out of its boundaries at each intersection. By observing 
what happened when the mesh was subdivided, I discovered that by adding very 
short faces in each direction from the point of intersection, the texture 
would stay within the desired boundaries. I am very pleased with the 
results.
BTW, I've been using build 9369, the one you made available on Sept. 30. The 
improvements are spectacular! Being able to divide several edges at once 
makes it possible to do things that would have been far too tedious to 
attempt before. Also, the fact that it highlights irregular faces that 
prevent subdivision. Having several hundred faces and not having a clue 
which ones were causing the problem was extremely frustrating. Thanks for 
fixing that.
Steve Shelby


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From: Steve Shelby
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 7 Nov 2004 09:50:38
Message: <418e363e$1@news.povray.org>
"Steve Shelby" <ssh### [at] shelbyvisioncom> wrote in message 
news:418d5abc$1@news.povray.org...
> BTW, I've been using build 9369, the one you made available on Sept. 30. 
> The improvements are spectacular! Being able to divide several edges at 
> once makes it possible to do things that would have been far too tedious 
> to attempt before. Also, the fact that it highlights irregular faces that 
> prevent subdivision. Having several hundred faces and not having a clue 
> which ones were causing the problem was extremely frustrating. Thanks for 
> fixing that.
> Steve Shelby

Something else I forgot to mention. I also appreciate the new feature which 
allows you to keep the same points, faces, or edges selected when switching 
back and forth between "modify" and "edit". That's very helpful.
Another thing that would be nice to have: a shortcut key for collapsing 
points.
Steve


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From: Txemi Jendrix
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 7 Nov 2004 11:32:23
Message: <418e4e17@news.povray.org>
Steve Shelby wrote:

> 
<snip>

> BTW, I've been using build 9369, the one you made available on Sept. 30.
> The improvements are spectacular! Being able to divide several edges at
> once makes it possible to do things that would have been far too tedious
> to attempt before. Also, the fact that it highlights irregular faces that
> prevent subdivision. Having several hundred faces and not having a clue
> which ones were causing the problem was extremely frustrating. Thanks for
> fixing that.

And how I can obtain the build 9369? It's not in Moray's site. (BTW I'm also
a registered user)

> Steve Shelby

-- 
Txemi Jendrix
www.txemijendrix.com


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From: Tim Cook
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 7 Nov 2004 11:32:53
Message: <418e4e35$1@news.povray.org>
Steve Shelby wrote:
> BTW, I've been using build 9369, the one you made available on Sept. 30.

Where might I get a copy?  I have 9330, which is what's on the official 
site.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

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From: Steve Shelby
Subject: Re: subdivision of mesh causes distortion of UV map
Date: 7 Nov 2004 12:44:45
Message: <418e5f0d$1@news.povray.org>
> And how I can obtain the build 9369? It's not in Moray's site. (BTW I'm 
> also
> a registered user)

Lutz sent an email with a link to it, not to the newsgroup, but to 
individuals, I assume they were those who had beta tested before. It looked 
to me at the time that his list of names was incomplete. If  he doesn't send 
in a reply here soon, maybe you could email him about it.
Steve Shelby


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